Basically title, but I can provide some information.
I’m looking to spend no more than $300 or so. I’m not well versed in different filaments (I’ll be honest, I know nothing) or really anything about 3d printing, but I want to be able to print cup holders for someone I know whose vehicle has none, I imagine heat resistance and strength would be important there. I also do robotics now and would like to be able to make my own small robot chassis and parts. I’m also a Linux user and like FOSS, which I believe is fairly compatible with 3d printing, so I would like to find a printer that doesn’t make me use proprietary software and that I can use with Fedora Linux without too much hassle. I know I’m new to this, and I know I’m in other hobbies where people post things like: “I want to spend no more than 6 dollars to get artificial superintelligence running on an Arduino Nano,” so I hope this isn’t that, and sorry if it is. Thanks in advance.
These days you can’t really go wrong with any bedslinger for a “first printer” since they are all Ender 3s anyway. That said, I think Teaching Tech just did a video where he talks about his suggested “first printer”. Get a bedslinger, use it for a few years, and then learn what you actually want out of a printer and go from there.
In terms of proprietary software: Many printers use some form of Klipper or Marlin (or can be reflashed to them) as firmware. In terms of a Slicer (what you use to go from model to instructions for your printer), Orcaslicer. Decide if those are FOSS enough for you.
The real issue is creating those models themselves. People will suggest FreeCAD. FreeCAD is great as a second or third modeling tool once you know the basics. But it is HORRIBLE for learning because so many terms and defaults are “different” than every other CAD program out there and the online resources are much more limited and are often referring to five or six major releases ago. The best of the best for a hobbyist is Fusion 360 but that explicitly does not work in Linux. I use OnShape which is web browser based (and all the pitfalls of that) and apparently has a legacy UX-wise going back to a tool I learned in high school.